Process for making electronic device

Abstract

Oxide films, and residues of organic matters, carbons, if any, are removed from a metal surface simply without using complicated steps and without giving adverse effects on electronic parts or electronic devices by irradiating the metal surface with a laser beam of lower energy level than energy capable of changing the metal surface structure, thereby cleaning the metal surface.

What is claimed is: 
     
       1. A process for a solder treatment, which comprises irradiating a surface of a solder bump or layer bonded to a ceramic substrate with a laser beam of lower energy level than energy capable of changing the solder surface structure, thereby cleaning the surface of said solder, and bonding an integrated circuit to said cleaned solder surface, said solder being comprised of Sn--Pb. 
     
     
       2. A process for making an electronic device, by connecting a part to a circuit wiring substrate by a solder, which comprises irradiating the solder with a laser beam, thereby cleaning the surface of the solder and then heating and melting the solder, thereby connecting the part to the circuit wiring substrate. 
     
     
       3. A process according to claim 2, wherein the part is a semiconductor integrated circuit. 
     
     
       4. A process according to claim 2, wherein the part is a seal cap of a semiconductor integrated circuit. 
     
     
       5. A process according to claim 2, wherein the circuit wiring substrate is a ceramic substrate. 
     
     
       6. A process for making an electronic device by connecting an LSI to a circuit substrate through a solder bump as a terminal, which comprises irradiating the solder bump with a laser beam, thereby cleaning the surface of the solder bump and then heating and melting the solder bump, thereby connecting the LSI to the circuit substrate. 
     
     
       7. A process according to claim 6, wherein the circuit substrate is a ceramic substrate. 
     
     
       8. A process according to claim 2, wherein the laser beam has a pulse span of not more than 1 microsecond. 
     
     
       9. A process according to claim 2, wherein the laser beam has a wavelength of 150 nm to 400 nm. 
     
     
       10. A process according to claim 2, wherein the laser beam has an energy density of 0.5 J/cm 2  to 4.0 J/cm 2 .